下列何者與肛直腸環(Anorectal ring)的構成無關？
恥骨直腸肌(Puborectalis muscle)
肛門內括約肌(Internal anal sphincter)
肛門外括約肌深部(Deep part of external anal sphincter)
肛門外括約肌淺部(Superficial part of external anal sphincter)
